As an avid Tumblr user I feel that it allows for the ultimate expression of creativity and personality. Utilizing its html options or the already created themes it allows for the user to have complete control. Also it has increasing gotten away from normal blog posting to sharing pictures and videos with you followers.This site is mainly used to waste time.
WordPress on the other hand is used for a more sophisticated level of social networking. People usually use this standard blog feel for a resume or something that employers would appreciate looking at. Writing and the actual content on this site is what is most important.